Title: Only Time Will Tell
By: angstytimelord
Pairing: gen
Fandom: Doctor Who
Rating: PG-13
Table: doctorwho_100 Prompt: 79, When?
Disclaimer: This is entirely a product of my own imagination, and I make no profit from it. I do not own the Tenth Doctor. Please do not sue.

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All of his companions left him. It was never a question of why -- he could always understand their reasons for going. It was only a question of when.

The Doctor sighed, clasping his hands behind his head and staring up at the blue sky above him. He'd come here to Earth to find a quiet place where he could think outside of the Tardis, and it seemed that he'd found that peace he sought.

It wasn't often that he looked for solitude, especially when he was companionless, as he was at the moment. But he'd been feeling rather melancholy lately, and he was determined to find out the cause for the depression that seemed to be striking at him.

It wasn't only that he didn't have a companion, he thought with a sigh. There were so many things that he felt were pressing down on him lately, things that he couldn't get away from. So much responsibility that he had to live up to.

There was always the worry that he wouldn't be able to avert the next disaster that could destroy the universe as he knew it. A worry that loomed large in his mind.

And of course, the constant vigilance he had to keep for the Master. He could never fully relax, never let his guard down. He'd discovered too many times in the past that it was all too easy for that wily madman to slip by that guard.

The Master had a way of breaking down his defenses when he least expected it. No matter how high he built the walls, that bastard seemed to be able to find a chink in his armor, to strike him at his weakest points and score a blow.

Fortunately, that blow had never been a killing one. At least, not yet. Not that the Master hadn't tried -- too many times to count over all the centuries of enmity between them. But he wouldn't succeed. The Doctor had vowed that long ago.

And he always kept his promises. Or tried to.

Again, his main concern with the Master wasn't if the other man would show up again. He always would; that was one of the constants of his life, doing battle with that psychopath time and time again. He was sure that battle would never end.

Not until one of them was vanquished, eradicated from existence forever. And truth be told, the Doctor wasn't sure which one of them he wanted it to be. He had his reasons for wanting the Master to continue on, even if they were selfish ones.

He didn't want to be the last. The last Time Lord, the last Gallifreyan. As long as the Master was still somewhere out there, roaming the galaxy, he wasn't completely alone. There was still someone who could understand what it was like to be who and what he was.

The Doctor sighed, shaking his head. Of course the Master could never understand what it was like to be him. They were so different. They always had been.

They would always be different. Even when they'd been friends, when they were children and young adults at the Academy, there had always been poles between them. The Master had evinced the beginning of his descent into madness even then.

He was still sliding down the slippery slope into complete insanity, no matter how much the Doctor tried to prevent that from happening. He'd given up on it, really. There was no way to stop what was inevitable; he had to accept that he couldn't save everyone.

Not even the man who had been his friend. He was helpless against the onslaught of the Master's egomaniacal madness that ate away at him from the inside. That was something that he couldn't fight, couldn't control, couldn't conquer.

Again, it wasn't a question of why the Master had gone mad. That question would never be answered. It was when he would strike again that worried the Doctor.

And when he would be able to find a new companion to be by his side, to help him through whatever challenges were to come in his future. Sometimes it seemed that he never would -- and that he might work better on his own.

But that seemed so unfair, condemning himself to a life of loneliness. Even though his companions were never lovers -- well, with the exception of Jack, and that had been a mistake -- he still needed to have someone there, a friend to talk to.

Unfortunately, most companions wanted more than that, more than he was ready or willing to give them. And that would make the friendship turn sour, over time. It had happened over and over again, and it really wasn't something he wanted to deal with.

The other question that hung in his mind was one that was much harder to answer than any other, and one that he didn't like to contemplate.

When was this all going to end? It was inevitable that he would eventually reach the end of his regenerations and find that it was time to end his sojourn in this realm. There was no longer any Gallifreyan high council to grant him an extension of regenerations.

He didn't want this to end. When it did, there would be no one to protect the galaxy -- it would be wide open to all kinds of predators like the Master, and much, much worse. The world's last defense would be gone; there would be no one to stand guard.

That was what he dreaded most. Not the manner of his moving from this realm into another, but that the timing of it would be the worst possible. He needed to be sure that he could leave this realm in peace, with a protector. No matter when it might happen.

But that was impossible to do. He would just have to hope that it didn't happen soon.

Sighing softly, the Doctor closed his eyes, wishing that he could erase all of these thoughts from his mind. Only time would tell just what was going to happen in his future -- and he would have to be ready to meet that future head on when it descended upon him.

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